Hickories
Carya
tonkinensis Lecomte, "Mai Chau", Vietnam hickory.
(This description is taken from Grauke, L.J.; Wood, B.W.; Payne, J.A. Genetic resources of Carya in Vietnam and China. Annu. Rpt. N. Nut Growers Assn. 82:80-87. 1991. )
Carya tonkinensis was first described by Henri Lecomte (1921)
based on leaves, flowers, fruits and wood sent by Lemarie from
Vietnam. The description was touted by Lecomte as "the first
genuine Carya described in full and belonging to a continent other
than North America". The description was thorough and has
been accepted without contest or revision by subsequent students
of the genus. The trees are known by the common name "Mai
chau" (or "May-chou") in Vietnam. In Yunnan province,
China, where the trees are native they are called "Lao-shu
he tao" or "Mouse walnuts" (Kuang & Li, 1979).
The trees are also refered to by a translation of the scientific
name as "Annam shan he tao" or "Vietnam hickory".
Carya tonkinensis is the mostly widely distributed of the Asian
Carya species. It has been reported from the "Son la region
of the Noire (Da) River" in Vietnam (Lecomte, 1921), and
in the nearby villages of Thuan, Mai-San, and Yen (Chevalier,
1941). In China, it has been reported from the following locations:
from Guangxi Province, Long-lin (Chang & Lu, 1979); from Yunnan
Province, "southern Yunnan bordering Cochinchina as well
as in the far Northwestern corner of Yunnan bordering Upper Burma"
(Hu, 1937); Kien-shuei Hsien, Shung-Kiang Hsien, Mienning, Yeanshui
(Stone, 1962); Salween divide (Tsai 54203 in Gray Herbarium);
Shuang bo, Jing-dong, Lin-cang, Shuang-jiang, Meng-zi, and Jing-ping
(Chang & Lu, 1979). The species has also been reported from
Assam Province, India, from near Kangpoki, Imphal, and Manipur
(Manning, 1963).
There are no reports of the cultivation of this tree, but
Louis (1921) reported on the extraction of oil from nuts for use
in cooking by Thai villagers in Vietnam. We collected nuts from
trees growing near a Thai village at Son la and were told that
nuts were collected for their oil. Bark from the trees was made
into a tea and given to women after childbirth to reduce bleeding.
On September 26, 1990, we collected from mature trees growing
on a hillside above the Ban Co Lay hamlet, Xa Chieng Sinh community,
about 3 km from Son la, Vietnam. The three U.S. scientists were
accompanied by the previously mentioned Vietnamese scientists
(Dung, Chinh, Nhi, and Dam) and by Dr Hoang Xuan Ty (Ecologist)
and Nguyen Trung Ve (Director, Northwest Forest Experiment Station).
Trees were up to 60 cm dbh, and 18 m tall. Some showed trunk
damage which may have been due to harvest procedures. Only a
light crop of nuts was available, most having already fallen or
been harvested. Nuts of five accessions of C. tonkinensis were
planted upon our return and seedlings have been produced in three
of those accessions, with of total of 11 seedlings growing.
Vietnam hickory is a deciduous tree with smooth, tight, grayish
bark. Current season shoots terminate in a cluster of bright
orange leaf buds, whose color is due to abundant orange peltate
scales. There are no bud scales. Leaves are odd pinnately compound
and up to 38 cm long including the petioles. Petioles are densely
hairy with very short hairs. There are usually 5-7 leaflets.
Lateral leaflets are opposite, ovate-lanceolate to oblanceolate,
acuminate, subrounded to cuneate at the base, and simply serrate.
The terminal leaflet and first pair of lateral leaflets are larger
than basipetal leaflets. Leaflets have reddish-orange peltate
scales on the abaxial surface and are puberulous along the midrib.
The adaxial midrib is puberulous. The subglobose nuts have a
characteristically flattened apex (2 cm length X 2.5 cm width
X 2.5 cm depth) are encased in a thin shuck (~2mm) which lacks
prominent wings on the sutures and dehisces into 4 segments.
Nuts are 1-celled
at the apex and 4-celled at the base.
LJ Grauke , Research
Horticulturist & Curator
USDA-ARS Pecan Genetics
10200 FM 50
Somerville, TX 77879
tele: 979-272-1402
fax: 979-272-1401
e-mail:
ljg@tamu.edu
Return
to Species
Index
Return to Species
Key
Go to Pecan
Cultivar Index
Go to Literature
Cited
Return to Main
Index